Willem Stoorvogel's Biography

Willem Stoorvogel,
Professor,
Utrecht University

During the last 20 years my research group has studied general molecular mechanisms that regulate endosome dynamics and sorting in these organelles of medically relevant cargo molecules, such as MHC class II. In professional antigen presenting cells, MHC class II is instrumental to initiate adaptive immune responses. Newly synthesised MHC class II is first loaded in endosomal compartments with antigen derived peptides and thereafter deposited at the cell surface. Regulation of these processes is one of the major elements of our current research. MHC class II is also incorporated into exosomes, which are small vesicles that are generated and secreted by endosomes. We study the immunological role of MHC class II carrying exosomes from antigen presenting cells. Another focus of our research group is the role of prostasomes, which are prostate epithelial cell derived exosomes found in semen.

During or directly after ejaculation, sperm cells are mixed with secretions from the prostate and other accessory sex glands. In addition to soluble constituents, seminal fluid from many mammalian species has been found to contain various types of extracellular vesicles, including prostasomes. Prostasomes are generated within and secreted by prostate epithelial cells in a process similar to the production of exosomes by other cell types. The proposed functions of prostasomes include prevention of immune-mediated destruction of spermatozoa within the female reproductive tract and modulation of the fertilizing capacity of sperm cells. How prostasomes could mediate such diverse functions, however, remains unclear. We identified and isolated two distinct classes of prostasomes on the basis of unique biochemical characteristics. This provides a means to study and assign specific functions to classes of prostasomes and to study their prognostic value for (sub) fertility and/or diseases such as prostate cancer.